There are certainly political ramifications, especially for Democratic governors. Here are some quotes from a NYTimes article that examined this issue.
http://www.nytimes.com/2014/04/06/u...ic-governors-resist-legalizing-marijuana.html
"The hesitance expressed by these (Democratic) governors reflects not only governing concerns but also, several analysts said, a historically rooted political wariness of being portrayed as soft on crime by Republicans."
“Either they don’t care about it as passionately or they feel embarrassed or vulnerable. They fear the judgment,” said Ethan Nadelmann, the founder of the
Drug Policy Alliance, an organization that favors decriminalization of marijuana. “The fear of being soft on drugs, soft on marijuana, soft on crime is woven into the DNA of American politicians, especially Democrats.”
He described that sentiment as, “Do not let yourself be outflanked by Republicans when it comes to being tough on crime and tough on drugs. You will lose.”
"There is no obvious political upside to supporting legalization, analysts said, and politicians, as a rule, tend to be risk averse."